1. Field of the Invention
The present invention relates to a masonry drill bit and particularly a masonry drill bit which has a drill body of a soft metal and a hardened carbide masonry drill bit insert inserted into the working end of said drill body.
2. Discussion of the Prior Art
Carbide-tipped masonry drills are fairly well known. A bit manufactured of tungsten carbide or other hardened material is inserted into a slot in the working end of a metallic shank, held in place utilizing a paste or other material which is replaced when the carbide insert is brazed within the slot. This practice, however, is very inaccurate in that the carbide insert is not oriented within the slot accurately and also prevents a clean braze. U.S. Pat. No. 3,447,616 teaches a drill having a detachable blade mounted on the end thereof in a slot extending transversely to the body of the drill. The blade is constructed with a hub having portions on opposite faces of the blade which fits into an opening formed into said slot so that the blade is oriented properly within the slot. U.S. Pat. No. 4,314,616 teaches a die-cast masonry drill with leading hard insert. The hardened insert is placed into the dies within which the drill body is to be cast. The drill body is cast in place around the insert with the molten material substantially surrounding the insert as well as interlocking means located on said insert. The insert is held into place within said slot by the contraction of the metal of the drill body due to differences in rates of thermal expansion.